TWI451199B - Resist underlayer film composition and patterning process using the same - Google Patents

Description

Photoresist underlayer film material and pattern forming method using the same

The present invention relates to a photoresist underlayer film material and a photoresist pattern forming method using the same, wherein the photoresist underlayer film material can be effectively used as an antireflection film material used for fine processing in a manufacturing step of a semiconductor element or the like, The photoresist pattern forming method using this material is suitable for far ultraviolet rays, KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), F ₂ laser light (157 nm), Kr ₂ laser light (146 nm), Ar ₂ A photoresist pattern forming method of laser light (126 nm), soft X-ray (EUV, 13.5 nm), electron beam (EB), X-ray exposure, or the like.

In recent years, with the increase in the density and speed of LSIs, and in the pursuit of miniaturization of the pattern size, how can the light source used be more subtle and high in the lithography that is used for light exposure as a general-purpose technology. Various techniques for the development of precision pattern processing are under development.

For the light source used for the lithography formed by the photoresist pattern, light exposure using a g-line (436 nm) or an i-line (365 nm) of a mercury lamp as a light source is widely used, and the exposure light is short for a method of miniaturization. The method of wavelengthization becomes effective. Therefore, in the mass production process of the 64M bit DRAM processing method, the i-line (365 nm) is replaced and the short-wavelength KrF excimer laser (248 nm) is used as the exposure light source. However, in order to manufacture DRAMs requiring a finer processing technique (processing size of 0.13 μm or less) and a density of 1 G or more, a light source of a shorter wavelength is required, and lithography using ArF excimer laser (193 nm) is particularly studied.

As a single-layer photoresist method used in a typical photoresist pattern forming method, when the height ratio (aspect ratio) of the pattern with respect to the pattern line width becomes large, there is often a case where the pattern collapses due to the surface tension of the developer during development. . Therefore, a high depth is formed on the step substrate In the case of a wide aspect pattern, a multilayer photoresist method in which a film having a different dry etching characteristic is known to form a pattern is excellent, and a two-layer photoresist method and a three-layer photoresist method are being studied, and two layers of the photoresist system are under study. A method in which a photoresist layer composed of a ruthenium-based photosensitive polymer and an organic polymer containing carbon, hydrogen, and oxygen as main constituent elements, for example, a phenolic polymer-based lower layer (Patent Document 1) The three-layer photoresist system has a combination of a photoresist layer composed of an organic photosensitive polymer for a single-layer photoresist method and an intermediate layer composed of a lanthanoid polymer or a lanthanide CVD film. The layer and the lower layer composed of an organic polymer (Patent Document 2).

In the underlayer film of the multilayer photoresist method, the lanthanide material layer directly above is used as a hard mask, and patterning by dry etching using oxygen is performed, so that an organic system using carbon and hydrogen and oxygen as main constituent elements is used. The polymer requires the etching resistance at the time of dry etching of the substrate to be processed, the film forming property of a film having high flatness on the substrate to be processed, and the antireflection function at the time of exposure depending on the method of use. For example, Patent Document 2 relates to a technique for a two-layer or three-layer underlayer film material for a photoresist method, and by using such an underlayer film, a lower layer film pattern can be formed with high precision, and etching conditions for a substrate to be processed can be ensured high. Etching resistance.

Here, FIG. 2 shows the substrate reflectance when the k value (extinction coefficient) of the photoresist interlayer film is changed.

As is clear from Fig. 2, when the k value of the photoresist intermediate layer film is a low value of 0.2 or less, a sufficient antireflection effect of 1% or less can be obtained by setting an appropriate film thickness.

3 and 4 show the change in reflectance when the k-value of the underlayer film is 0.2 and 0.6 times when the film thickness of the intermediate layer and the lower layer is changed. As can be seen from a comparison between Fig. 3 and Fig. 4, the k value of the photoresist underlayer film is high (0.6 (Fig. 4)), and the reflection can be suppressed to 1% or less compared with the film. When the k value of the photoresist underlayer film was 0.2 (Fig. 3), and the film thickness was 250 nm, the film thickness of the photoresist interlayer film had to be increased in order to make the reflection 1%. When the film thickness of the photoresist intermediate layer film is raised, the dry etching of the photoresist intermediate layer film is large, and the load on the uppermost layer photoresist is large, which is not preferable. Figures 3 and 4 show that the NA of the lens of the exposure device is In the case of the dry exposure of 0.85, the n value (refractive index), the k value, and the film thickness of the intermediate layer of the three-layer process are optimized, and the reflectance can be made 1% or less regardless of the k value of the underlayer film.

However, with the immersion lithography, the NA of the projection lens exceeds 1.0, and the angle of light incident on the resist and incident on the anti-reflection film under the photoresist is also shallow. The antireflection film not only utilizes the absorption of the film itself, but also suppresses reflection by the destructive action of the interference effect of light. Since the interference effect of the oblique light light becomes small, the reflection increases.

In the film of the three-layer process, the intermediate layer is used to resist reflection by the interference of light. Since the underlayer film is extremely thick in order to utilize the interference effect, there is no destructive antireflection effect by the interference effect. The reflection from the surface of the underlying film must be suppressed, so it is necessary to make the value of k less than 0.6 and the value of n close to the value of the intermediate layer of the upper layer. If the k value is too small, the transparency is too high, and the reflection from the substrate occurs, so the NA1.3 of the immersion exposure is particularly preferable. The combination of k values is about n/k = 1.50/0.30-0.35.

When the underlying film is used as a mask to etch the substrate to be processed, it is pointed out that the underlying film is distorted and bent (Non-Patent Document 1). An amorphous carbon film (hereinafter referred to as CVD-C) produced by CVD is known to be very effective in preventing distortion by making hydrogen atoms in the film extremely small.

However, when the substrate to be processed of the substrate has a step, it is necessary to flatten the step by using the underlayer film. By flattening the underlayer film, it is possible to suppress variation in film thickness of the intermediate layer and the photoresist formed thereon, and to expand the focal length margin of the lithography.

It is difficult to flatten the step difference by using a CVD-C film using methane gas, ethane gas, acetylene gas or the like as a raw material. On the contrary, when the underlayer film is formed by spin coating, there is an advantage that the unevenness of the substrate can be embedded.

As described above, the CVD-C film has poor embedding characteristics of the step, and further, the CVD apparatus often has difficulty in introduction because of the high price and the area occupied by the bottom area of the device. condition. If the underlying film material which can be formed by spin coating can be used to solve the problem of distortion, it has considerable advantages in terms of process and equipment simplification.

Patent Document 3, an attempt is made to form a good photoresist pattern by applying a polycyclic aliphatic ring by using a polycyclic aliphatic ring in a main chain of a polymer of a rectifying unit contained in a composition under a photoresist, but a polymer main chain It is a polyester or a polyether, and has low etching resistance and poor pattern bending resistance, so it is not suitable for the purpose.

Therefore, an underlayer film material having an optimum n and k value as an antireflection film, and excellent in embedding characteristics and pattern bending resistance, and which does not cause distortion during etching, has been sought.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 6-118651

[Patent Document 2] Japanese Patent No. 4355943

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-093162

[Non-patent literature]

[Non-Patent Document 1] Proc. of Symp. Dry. Process, (2005) p11

In order to solve the above problems, the present invention provides a photoresist underlayer film material comprising at least one compound represented by the following general formula (1-1) and/or (1-2), and A polymer obtained by condensing one or more compounds represented by the following formula (2) with one or more compounds represented by the following formula (3) and/or their equivalents.

(In the above formulae (1-1) and (1-2), R ¹ to R ⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an isocyanate group, a glycidoxy group, a carboxyl group, an amine group, or a carbon number. Any one of an alkoxy group of 1 to 30, an alkoxycarbonyl group having 1 to 30 carbon atoms, an alkoxycarbonyl group having 1 to 30 carbon atoms, or a saturated or unsaturated organic group having 1 to 30 carbon atoms which may be substituted Further, two substituents arbitrarily selected from R ¹ to R ⁴ or R ⁵ to R ^{8 may} be bonded to each other to form a cyclic substituent.

(In the above formula (2), X is an integer of 2 to 4.)

Y-CHO (3)

(In the above formula (3), Y is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms which may be substituted.)

The photoresist underlayer film formed by using the photoresist underlayer film material as described above can exhibit an excellent anti-reflection film function for short-wavelength exposure, that is, high transparency, optimum n value, k value, and substrate processing. The pattern has excellent bending resistance.

Further, the photoresist underlayer film material may further contain a crosslinking agent, an acid generator, and an organic One or more of the solvents.

In this way, the photoresist underlayer film material of the present invention can further improve the coating property of the photoresist underlayer film material or the like on the substrate by further containing one or more of a crosslinking agent, an acid generator, and an organic solvent. After the coating, the crosslinking reaction in the underlayer film of the photoresist can be promoted by baking or the like. Therefore, there is little concern that the above-mentioned photoresist underlayer film and the photoresist upper layer film are mixed with each other, and the molecular component diffuses to the photoresist upper layer film.

Moreover, the present invention provides a pattern forming method for forming a pattern on a workpiece, characterized in that it comprises at least the steps of forming a photoresist underlayer film on the object to be processed using the photoresist underlayer film material, and On the photoresist underlayer film, a photoresist intermediate layer film material is formed using a germanium-containing photoresist intermediate layer film material, and a photoresist upper layer film material is used to form light on the photoresist intermediate layer film. Blocking the upper layer film, forming a circuit pattern on the photoresist upper layer film, etching the photoresist intermediate layer film by using the patterned photoresist upper layer film as a mask, and using the patterned photoresist intermediate layer film as a mask The photoresist underlayer film is etched, and the processed object is etched by using the patterned photoresist underlayer film as a mask to form a pattern on the object to be processed.

As described above, by using the photoresist underlayer film material of the present invention to form a pattern by lithography, a pattern can be formed on the substrate with high precision.

Moreover, the present invention provides a pattern forming method for forming a pattern on a workpiece, characterized in that it comprises at least the steps of forming a photoresist underlayer film on the object to be processed using the photoresist underlayer film material, and On the photoresist underlayer film, a photoresist interlayer film is formed using a germanium-containing photoresist interlayer film material, and an organic anti-reflection film (BARC) is formed on the photoresist interlayer film, and on the BARC Forming a photoresist upper layer film using the photoresist upper layer film material of the photoresist composition to form a 4-layer photoresist film, forming a circuit pattern on the photoresist upper layer film, and using the patterned photoresist upper layer film as a mask Etching the BARC and the photoresist interlayer film, and forming the film The patterned photoresist intermediate layer film is used as a mask to etch the photoresist underlayer film, and further, the patterned photoresist underlayer film is used as a mask to etch the object to be processed, and a pattern is formed on the object to be processed. .

As such, in the pattern forming method of the present invention, the BARC can be formed between the photoresist interlayer film and the photoresist upper film.

Moreover, the present invention provides a pattern forming method for forming a pattern on a workpiece, characterized in that it comprises at least the following steps: forming a photoresist underlayer film using the photoresist underlayer film material on a workpiece, and An inorganic hard mask interlayer film selected from any one of a tantalum oxide film, a tantalum nitride film, a tantalum oxide film, and an amorphous tantalum film is formed on the underlayer film of the photoresist, and the inorganic hard mask is formed on the inorganic hard mask. On the mask intermediate film, a photoresist upper film is formed by using a photoresist upper film material of the photoresist composition, and a circuit pattern is formed on the photoresist upper film, and the patterned photoresist upper film is used as a mask to be etched. In the inorganic hard mask interlayer film, the photoresist underlayer film is etched by using the patterned inorganic hard mask interlayer film as a mask, and further, the patterned photoresist underlayer film is used as a mask. The object to be processed is etched to form a pattern on the object to be processed.

As described above, in the pattern forming method of the present invention, even in the case where an inorganic hard mask interlayer film is used, it is possible to form a pattern by using the photoresist underlayer film material of the present invention and form a pattern by lithography, which can be accurately performed on the substrate. Form a pattern.

Moreover, the present invention provides a pattern forming method for forming a pattern on a workpiece, characterized in that it comprises at least the steps of forming a photoresist underlayer film on the object to be processed using the photoresist underlayer film material, and An inorganic hard mask interlayer film selected from the group consisting of a tantalum oxide film, a tantalum nitride film, a tantalum oxide film, and an amorphous tantalum film is formed on the underlayer film of the photoresist, and is harder than the inorganic hard mask. An organic anti-reflection film (BARC) is formed on the interlayer film, and a photoresist upper film is formed on the BARC by using a photoresist upper layer film material to form a photoresist film, and a photoresist layer is formed on the photoresist. upper layer Forming a circuit pattern, and etching the BARC and the inorganic hard mask interlayer film by using the patterned photoresist upper film as a mask, and using the patterned inorganic hard mask interlayer film as a mask The photoresist underlayer film is etched, and the processed object is etched by using the patterned photoresist underlayer film as a mask to form a pattern on the object to be processed.

As described above, if the BARC is formed on the hard mask interlayer film, the two-layer anti-reflection film can suppress reflection even at an immersion exposure of a NA exceeding 1.0. Moreover, it also has the effect of reducing the smear of the photoresist pattern on the hard mask interlayer film.

In this case, the aforementioned inorganic hard mask interlayer film can be formed by a CVD method or an ALD method.

As described above, the etching resistance can be improved by forming the inorganic hard mask interlayer film by the CVD method or the ALD method.

Further, the pattern forming method of the photoresist upper layer film may be any one of light lithography having a wavelength of 10 nm or more and 300 nm or less, direct drawing by an electron beam, and nanoimprint, or a combination thereof to form a pattern. .

As described above, a pattern can be formed on the photoresist upper layer film by any one of light lithography having a wavelength of 10 nm or more and 300 nm or less, direct drawing by an electron beam, and nanoimprinting, or a combination thereof.

Further, the developing method of the pattern forming method is preferably alkali development or development using an organic solvent.

As described above, in the present invention, alkali development or development using an organic solvent can be applied.

Further, as the object to be processed, any one of a metal film, a metal carbide film, a metal oxide film, a metal nitride film, and a metal oxide nitride film may be formed on the semiconductor substrate.

In this case, any of tantalum, titanium, tungsten, cerium, zirconium, chromium, lanthanum, copper, aluminum, and iron, or an alloy thereof may be used as the metal.

As described above, in the present invention, the film-formed body may be formed by any one of a metal film, a metal carbide film, a metal oxide film, a metal nitride film, and a metal oxide nitride film on the semiconductor substrate, for example. The foregoing metals may be any of ruthenium, titanium, tungsten, ruthenium, zirconium, chromium, ruthenium, copper, aluminum, and iron, or alloys thereof.

As described above, the photoresist underlayer film formed by the photoresist underlayer film material of the present invention exhibits a function as an excellent antireflection film, particularly for short-wavelength exposure, that is, has high transparency and has an optimum n. The value and the k value are excellent in the embedding property, and are excellent in pattern bending resistance at the time of substrate processing. Further, by forming a pattern using the photoresist underlayer film material of the present invention, the upper layer resist pattern can be transferred with high precision on the object to be processed.

(Formation of implementing the invention)

The following description relates to the present invention.

As described above, the high density and high speed of LSI are progressing, and an underlayer film material and a pattern forming method are sought, which have the following characteristics: optimum n, k value and embedding property as an antireflection film, and excellent The pattern is curved and resistant to distortion in the etch.

In view of the above, the inventors of the present invention have found that the pattern bending resistance is high, and in particular, the underlayer film for the multilayer photoresist process in which the line is not collapsed or twisted after the etching is performed on the 60 nm deep high aspect ratio line. An underlayer film obtained from a composition containing an adamantane skeleton having a rigid structure and a polymer containing an aldehyde compound, which has a high film strength (hardness) measured by a nanoindentation method, and thus no etching is found. The collapse or distortion of the subsequent line occurs, and the optimum optical characteristics (n value, k value) which can be used as an antireflection film are completed, and the present invention has been completed.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

The present invention relates to a photoresist underlayer film material comprising at least one or more compounds represented by the following general formulae (1-1) and/or (1-2), and one or more kinds thereof. The compound represented by the following formula (2) is condensed with one or more compounds represented by the following formula (3) and/or their equivalents (hereinafter also referred to as "aldehyde compound (3)"). Polymer.

(In the above formulae (1-1) and (1-2), R ¹ to R ⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an isocyanate group, a glycidoxy group, a carboxyl group, an amine group, or a carbon number. Any one of an alkoxy group of 1 to 30, an alkoxycarbonyl group having 1 to 30 carbon atoms, an alkoxycarbonyl group having 1 to 30 carbon atoms, or a saturated or unsaturated organic group having 1 to 30 carbon atoms which may be substituted Further, two substituents arbitrarily selected from R ¹ to R ⁴ or R ⁵ to R ^{8 may} be bonded to each other to form a cyclic substituent.

(In the above formula (2), X is an integer of 2 to 4.)

Y-CHO (3)

(In the above formula (3), Y is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms which may be substituted.)

Here, the organic group of the present invention means a carbon-containing group, and may further contain hydrogen, and may also contain nitrogen, oxygen, sulfur, or the like.

As long as it is a photoresist underlayer film material containing such a polymer, the underlayer film obtained thereby can function as an excellent antireflection film especially for short-wavelength exposure, that is, has transparency and has an optimum n value. It has a k value and is excellent in pattern bending resistance at the time of substrate processing.

Naphthalene (derivative) represented by the above formula (1-1) (hereinafter also referred to as "naphthalene derivative (1-1)"), for example, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 1,3-Dimethylnaphthalene, 1,5-dimethylnaphthalene, 1,7-dimethylnaphthalene, 2,7-dimethylnaphthalene, 2-vinylnaphthalene, 2,6-divinylnaphthalene , anthracene naphthalene, terpene, anthracene, 1-methoxynaphthalene, 2-methoxynaphthalene, 1,4-dimethoxynaphthalene, 2,7-dimethoxynaphthalene, 1-naphthol, 2- Naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene , 2,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2 , 7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 5-amino-1-naphthol, 2-methoxycarbonyl-1-naphthol, 1-(4-hydroxyphenyl)naphthalene, 6-( 4-hydroxyphenyl)-2-naphthol, 6-(cyclohexyl)-2-naphthol, 1,1'-bi-2,2'-naphthol, 6,6'-linked-2,2' - naphthol, 9,9-bis(6-hydroxy-2-naphthyl)anthracene, 6-hydroxy-2-vinylnaphthalene, 1-hydroxymethylnaphthalene, 2-hydroxymethylnaphthalene, and the like.

Further, benzene (derivative) represented by the above formula (1-2) (hereinafter also referred to as "benzene derivative (1-2)"), for example, toluene, o-xylene, m-xylene, p-xylene , cumene, indoline, hydrazine, mesitylene, biphenyl, anthracene, phenol, anisole, o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol, 2,5 - dimethyl phenol, 3,4-dimethyl phenol, 3,5-dimethyl phenol, 2,4-dimethyl phenol, 2,6-dimethyl phenol, 2,3,5-trimethyl Phenol, 3,4,5-trimethylphenol, 2-tert-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, isophthalic acid Phenol, 2-methyl resorcinol, 4-methyl resorcinol, 5-methyl resorcinol, catechol, 4-t-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propyl phenol, 3-propyl phenol, 4-propyl phenol, 2-isopropyl phenol, 3-isopropyl phenol, 4-isopropyl phenol, 2-methoxy 5-methylphenol, 2-tert-butyl-5-methylphenol, 4-phenylphenol, tritylphenol, benzenetriol, thymol, phenyl glycidyl ether, 4- Fluorophenol, 3,4-difluorophenol, 4-trifluoromethylphenol, 4-chlorophenol, 9,9-bis(4-hydroxyphenyl)fluorene, styrene, 4-tert-butoxybenzene Ethylene, 4-acetoxy styrene, 4-methoxystyrene, divinylbenzene, benzyl alcohol, and the like.

The compounds represented by the above formulas (1-1) and (1-2) may be used singly or in combination, and in order to control the n value, the k value, and the etching resistance, two or more types may be combined.

An example of the adamantane compound (hereinafter also referred to as "adamantane compound (2)") represented by the above formula (2) can be represented by the following formula.

The ratio of the naphthalene derivative (1-1), the benzene derivative (1-2) to the adamantane compound (2), and the total amount of the molar amount of the naphthalene compound (1-1) and the benzene compound (1-2) The amount of 1 mole is 0.01 to 5 moles, preferably 0.1 to 2 moles.

An aldehyde compound represented by the above formula (3), such as formaldehyde, three , trioxane, acetaldehyde, propionaldehyde, adamantane formaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropanal, β-phenylpropanal, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, adjacent Nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, p-n-butylbenzaldehyde, 1- Naphthyl formaldehyde, 2-naphthyl formaldehyde, furfural, hydrazine formaldehyde, furaldehyde, methylal, and the like.

Further, an equivalent of the aldehyde compound shown herein can be used. For example, the equivalent of the above formula (3) may, for example, be of the following formula:

(Y is the same as defined above, and R' may be a monovalent hydrocarbon group having 1 to 10 carbon atoms which are the same or different.)

(Y is the same as defined above, and R" is a divalent hydrocarbon group having 1 to 10 carbon atoms.) or when a hydrogen atom is bonded to the α-carbon atom of the indenyl group:

(Y' is an organic group having one hydrogen atom less than the above Y, and R' is a monovalent hydrocarbon group having 1 to 10 carbon atoms.).

The polymer as described above contained in the photoresist underlayer film material of the present invention is, for example, represented by the following formula (4-1) or (4-2).

(In the above formulae (4-1) and (4-2), R ¹ to R ⁸ and Y are the same as described above, and X' and X" are integers of 0 to 2. A, b, c, and d are all repeats. The ratio of each unit in the unit satisfies the relationship of a+b+c+d≦1.)

Ratio of naphthalene derivative (1-1), benzene derivative (1-2), aldehyde compound (2) and aldehyde compound (3), relative to naphthalene derivative (1-1) and benzene derivative (1- 2) The total amount of moles per mole is 0.01 to 5 moles, preferably 0.05 to 2 moles.

The ratio in all repeating units is preferably 0.1 < a + b < 1, more preferably 0.3 < a + b < 0.95.

A polymer derived from the above-mentioned starting material (compound) (expressed by the above formula (4-1) or (4-2)), usually in the absence of a solvent or in a solvent, using an acid or a base as a catalyst, The above-mentioned corresponding compound is subjected to a condensation reaction (for example, dehydration condensation) at room temperature or, if necessary, under cooling or heating.

The solvent used, for example: methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol, diethylene glycol, glycerol, methyl cyproterone, ethyl cyanidin, butyl cyanisol, An alcohol such as propylene glycol monomethyl ether; an ether such as diethyl ether, dibutyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran or 1,4-dioxane; methylene chloride; Chlorine-based solvents such as chloroform, dichloroethane and trichloroethylene; hexane, heptane, benzene, Hydrocarbons such as toluene, xylene, and cumene; nitriles such as acetonitrile; ketones such as acetone, methyl ethyl ketone, and isobutyl methyl ketone; esters such as ethyl acetate, n-butyl acetate, and propylene glycol methyl ether acetate a lactone such as γ-butyrolactone; an aprotic polar solvent such as dimethyl hydrazine, N,N-dimethylformamide or trimethylamine hexamethylphosphate, which may be used alone or in combination. More than 2 types are used. These solvents can be used in the range of 0 to 2,000 parts by mass based on 100 parts by mass of the reaction raw material.

As the acid catalyst to be used, inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and heteropolyacids; oxalic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid; Organic acids such as acid and trifluoromethanesulfonic acid; aluminum trichloride, aluminum ethoxide, aluminum isopropoxide, boron trifluoride, boron trichloride, boron tribromide, tin tetrachloride, tin tetrabromide , dibutyltin dichloride, dibutyldimethoxytin, dibutylmethoxy tin, titanium tetrachloride, titanium tetrabromide, titanium (IV) tetraethoxide, titanium (IV) tetraethoxide, tetraiso Lewis acid such as titanium (IV) propoxide or titanium oxide (IV). The alkali catalyst to be used may be an inorganic base such as sodium hydroxide, potassium hydroxide, barium hydroxide, sodium carbonate, sodium hydrogencarbonate, potassium carbonate, lithium hydride, sodium hydride, potassium hydride or calcium hydride; An alkyl group such as lithium, n-butyllithium, methylmagnesium chloride or ethylmagnesium bromide; an alkoxy compound such as sodium methoxide, sodium ethoxide or potassium n-butoxide; triethylamine or diisopropylethylamine An organic base such as N,N-dimethylaniline, pyridine or 4-dimethylaminopyridine. The amount thereof to be used is in the range of 0.001 to 100% by weight, preferably 0.005 to 50% by weight based on the raw material. The reaction temperature is preferably from -50 ° C to about the boiling point of the solvent, more preferably from room temperature to 100 ° C.

The condensation reaction method includes a method of adding a naphthalene derivative (1-1), a benzene derivative (1-2), an adamantane compound (2), an aldehyde compound (3), and a catalyst, or a catalyst. There is a method in which a naphthalene derivative (1-1), a benzene derivative (1-2), an adamantane compound (2), an aldehyde compound (3), and the like are added dropwise.

After completion of the condensation reaction, in order to remove unreacted raw materials, catalysts, and the like which are present in the reaction system, the following methods may be used depending on the properties of the obtained reaction product: the temperature of the reaction vessel is raised to 130 to 230 ° C. Go at about 1~50mmHg A method of separating a polymer by a method of dissolving a volatile component or a method of appropriately adding a solvent or water, a method of dissolving a polymer in a poor solvent, and then reprecipitating it in a poor solvent.

The polystyrene-converted molecular weight of the polymer thus obtained preferably has a weight average molecular weight (Mw) of 500 to 500,000, particularly preferably 1,000 to 100,000. The molecular weight dispersion degree (Mw/Mn) is preferably in the range of 1.2 to 20, and the monomer component, the oligomer component, or the low molecular weight body having a molecular weight (Mw) of 1,000 or less is removed, and the volatile component in baking is suppressed. It can prevent surface defects caused by contamination or volatile components around the baking cup.

Further, a condensed aromatic or alicyclic substituent may be introduced into the polymer.

Here, the substituent which can be introduced is specifically, for example, the following.

Among these, in the case of 248 nm exposure, it is preferred to use a polycyclic aromatic group, for example. Such as 蒽 methyl, 芘 methyl. In order to improve the transparency at 193 nm, it is preferred to use an alicyclic structure or a naphthalene structure. On the other hand, at a wavelength of 157 nm, the benzene ring has a spectral window with improved transparency, so it is necessary to change the absorption wavelength to enhance absorption. The furan ring absorbs shorter wavelength than the benzene ring, and the absorption at 157 nm is slightly improved, but the effect is poor. The naphthalene ring, the anthracene ring, and the anthracene ring increase absorption due to the long wavelength of the absorption wavelength, and these aromatic rings also have an effect of improving the etching resistance, and are suitable for use.

The introduction method of the substituent, for example, an alcohol in which a bond position of the above substituent in the polymer is a hydroxyl group, and an aromatic electrophilic substitution reaction mechanism in the presence of an acid catalyst, and an ortho or a pair of a hydroxyl group or an alkyl group is introduced. Bit method. As the acid catalyst, an acidic catalyst such as hydrochloric acid, nitric acid, sulfuric acid, formic acid, oxalic acid, acetic acid, methanesulfonic acid, n-butanesulfonic acid, camphorsulfonic acid, p-toluenesulfonic acid or trifluoromethanesulfonic acid can be used. The amount of the acidic catalyst used is 0.001 to 20 parts by mass based on 100 parts by mass of the polymer before the reaction. The amount of introduction of the substituent is in the range of 0 to 0.8 mol with respect to 1 mol of the monomer unit in the polymer.

In addition, it can also be blended with other polymers. The polymer to be blended is, for example, a compound represented by the above formula (1-1) or formula (1-2) as a raw material, a polymer having a different composition, a known phenol resin or the like. These are mixed, and have a function of improving the film forming property of the spin coating and the embedding property of the step substrate. Further, a material having a high carbon density and high etching resistance can be selected.

For example, a known phenolic resin which can be used for blending, specifically, for example, phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,5-xylenol, 3,4 -xylenol, 3,5-xylenol, 2,4-xylenol, 2,6-xylenol, 2,3,5-trimethylol, 3,4,5-trimethylphenol, 2- Tributylphenol, 3-tertiol, 4-tert-butylphenol, 2-phenol, 3-phenol, 4-phenol, 3,5-diphenol, 2-naphthol, 3-naphthol, 4-naphthalene Phenol, 4-tritresol, resorcinol, 2-methyl resorcinol, 4-methyl resorcinol, 5-methyl resorcinol, catechol, 4-third Butyl catechol, 2-methoxyphenol, 3-methoxyphenol, 2-propanol, 3-propanol, 4-propanol, 2-propofol, 3-propofol, 4-isopropyl Phenol, 2-methoxy-5-cresol, 2-tert-butyl-5-cresol, gallic phenol, thymol, iso-thymol, 4,4'-(9H-茀-9-subunit Bisphenol, 2,2'-dimethyl-4,4'-(9H-茀-9-ylidene)bisphenol, 2,2'-diallyl-4,4'-(9H-茀-9-subunit)bisphenol, 2,2'-difluoro-4,4'-(9H-茀-9-ylidene)bisphenol, 2,2'biphenyl-4,4'-(9H -茀-9-subunit)bisphenol, 2,2'-dimethoxy-4,4'-(9H-茀-9-ylidene)bisphenol, 2,3,2',3'-four hydrogen -(1,1')-spirobifluorene-6,6'-diol, 3,3,3',3'-tetramethyl-2,3,2',3'-tetrahydro-(1, 1')-spirobipurine-6,6'-diol, 3,3,3',3',4,4'-hexamethyl-2,3,2',3'-tetrahydro-(1 , 1')-spirobifluorene-6,6'-diol, 2,3,2',3'-tetrahydro-(1,1')-spirobi-5,5'-diol, 5 ,5'-Dimethyl-3,3,3',3'-tetramethyl-2,3,2',3'-tetrahydro-(1,1')-spirobi-6,6' -diol, 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol, 1,5- Dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, etc., dihydroxynaphthalene, 3-hydroxy-naphthalene-2-carboxylic acid, hydroxyanthracene, hydroxyindole (Hydroxyanthracene), bisphenol, phenol And dehydration condensate with formaldehyde, polystyrene, polyvinyl naphthalene, polyethylene, polyvinyl carbazole, polyfluorene, polydecene, polycondensation Alkene, polycyclododecene, polytetracyclododecene, polynortricyclopentane, poly(meth)acrylate, and the like.

In addition, it can also be blended: other well-known nor-tricyclic ruthenium copolymers, hydrogenated naphthol phenolic resins, naphthol dicyclopentadiene copolymers, phenol biscyclopentadiene copolymers, terpene copolymers, ruthenium copolymers a phenol-based fullerene, a bisphenol compound and a phenol resin thereof, a dibisphenol compound and a phenol resin thereof, a phenolic resin of an adamantane phenol compound, a hydroxyvinylnaphthalene copolymer, a bis-naphthol compound, and a phenol resin thereof, A resin compound represented by a ROMP polymer or a tricyclopentadiene copolymer, a fullerene resin compound, or the like.

The compounding amount of the compound for blending or the blending polymer is one or more compounds represented by the above formula (1-1) and/or (1-2), and one or more of the above formulas are used. The total amount of the compound represented by 2) or more of the compound represented by the above formula (3) and/or its equivalent is 0 to 1000 parts by mass, preferably 0 to 500 parts by mass.

The photoresist underlayer film material of the present invention may contain a crosslinking agent, the purpose of which is: After coating the substrate or the like, baking or the like can promote the crosslinking reaction in the underlayer film of the photoresist, reduce the mutual miscibility of the photoresist underlayer film and the photoresist upper layer film, and reduce the diffusion of low molecular components to the upper layer of the photoresist. The condition of the membrane.

The crosslinking agent which can be used in the present invention can be added to the materials described in paragraphs (0055) to (0060) of JP-A-2007-199653.

In the present invention, an acid generator for further promoting the crosslinking reaction due to heat may be added. The acid generator may be arbitrarily added if it generates acid due to thermal decomposition or generates acid due to light irradiation. Specifically, the materials described in paragraphs (0061) to (0085) of JP-A-2007-199653 can be added.

Further, in the photoresist underlayer film material used in the pattern forming method of the present invention to be described later, a basic compound for improving storage stability can be blended. The basic compound prevents the crosslinking reaction promoted by a trace amount of acid generated from the acid generator and functions as a quencher for the acid.

As such a basic compound, a material described in paragraphs (0086) to (0090) of JP-A-2007-199653 can be specifically added.

Further, in the preparation of the photoresist underlayer film material of the present invention, an organic solvent can be used.

The organic solvent which can be used in the preparation of the photoresist underlayer film material of the present invention is not particularly limited as long as it can dissolve the polymer, the acid generator, the crosslinking agent, other additives, and the like. Specifically, the solvent described in paragraphs (0091) to (0092) of JP-A-2007-199653 can be added.

Further, in the photoresist underlayer film forming material used in the pattern forming method of the present invention, a surfactant may be added in order to improve the coating property of spin coating. As the surfactant, those described in paragraphs (0165) to (0166) of JP-A-2008-111103 can be used.

The pattern forming method of the present invention using the photoresist underlayer film material prepared in the above manner can be exemplified as follows.

The present invention provides a pattern forming method for forming a pattern on a workpiece, characterized in that it comprises at least the following steps: forming a photoresist underlayer film on the object to be processed using the photoresist underlayer film material of the present invention, And forming a photoresist intermediate layer film on the underlying film of the photoresist, using a photoresist film containing a germanium atom, and using a photoresist upper layer film material on the photoresist intermediate layer film. Forming a photoresist upper layer film, forming a circuit pattern on the photoresist upper layer film, etching the photoresist intermediate layer film by using the patterned photoresist upper layer film as a mask, and forming the patterned photoresist intermediate layer The film is etched as a mask to etch the underlayer film, and further, the formed object is etched by using the patterned photoresist underlayer film as a mask to form a pattern on the object to be processed.

In the step of forming a photoresist underlayer film in the pattern forming method of the present invention, the above-mentioned photoresist underlayer film material is applied onto the object to be processed by a spin coating method or the like in the same manner as the photoresist. Good embedding characteristics can be obtained by using a spin coating method or the like. After spin coating, the solvent is evaporated, and baking to promote the crosslinking reaction is carried out in order to prevent mixing with the photoresist upper film or the photoresist intermediate film. The baking is carried out in the range of more than 100 ° C and 600 ° C or less for 10 to 600 seconds, preferably 10 to 300 seconds. The baking temperature is preferably 150 ° C or more and 500 ° C or less, more preferably 180 ° C or more and 400 ° C or less. The upper limit of the heatable temperature of the lithography wafer process is 600 ° C or less, preferably 500 ° C or less, in consideration of the influence of component damage or wafer deformation.

The gas atmosphere during baking may be in the air, but it is preferred to encapsulate an inert gas such as N ₂ , Ar or He in order to reduce oxygen, since oxidation of the photoresist underlayer film can be prevented. The oxygen concentration must be controlled in order to prevent oxidation, and is preferably 1,000 ppm or less, more preferably 100 ppm or less. It is preferable to prevent oxidation of the underlayer film of the photoresist in baking, since absorption is not increased and etching resistance is lowered.

In addition, the thickness of the photoresist underlayer film can be appropriately selected, but should be determined as 30~20,000nm, especially 50~15,000nm. After the photoresist underlayer film is formed, in the case of a three-layer process, a photoresist-containing interlayer film containing germanium and a photoresist-free upper film (single-layer photoresist film) containing no germanium may be formed thereon.

Such a three-layer process of the ruthenium-containing photoresist intermediate layer film is preferably an interlayer film using a polyoxyalkylene group. By providing the yttrium-containing intermediate layer with an effect as an anti-reflection film, reflection can be suppressed. Specifically, for example, a polysiloxane-containing material represented by JP-A-2004-310019, 2007-302873, and 2009-126940.

In particular, for 193 nm exposure, when a material having a high etching resistance of a substrate containing a large number of aromatic groups is used as a photoresist underlayer film, the k value becomes high and the substrate reflection becomes high, but the reflection is suppressed by the photoresist interlayer film. The substrate is reflected to be 0.5% or less.

When an inorganic hard mask intermediate layer film is formed on the photoresist underlayer film, a tantalum oxide film, a tantalum nitride film, a tantalum oxide film (SiON film), or an amorphous germanium film is formed by a CVD method, an ALD method, or the like. A method of forming a nitride film is described in JP-A-2002-334869 and WO2004/066377. The film thickness of the inorganic hard mask is 5 to 200 nm, preferably 10 to 100 nm, and it is preferable to use a SiON film having a high effect as an antireflection film. Since the substrate temperature at the time of forming the SiON film is 300 to 500 ° C, the lower film must be able to withstand the temperature of 300 to 500 ° C. The photoresist underlayer film material used in the present invention has high heat resistance and can withstand a high temperature of 300 to 500 ° C. Therefore, an inorganic hard mask formed by a CVD method or an ALD method and a photoresist underlayer film formed by a spin coating method are used. Combination is feasible.

A photoresist film as a photoresist upper film may also be formed on the photoresist interlayer film and the inorganic hard mask interlayer film, or may be formed on the photoresist interlayer film and the inorganic hard mask interlayer film. An organic anti-reflection film (BARC) is formed by spin coating, and a photoresist film is formed thereon.

In particular, when an inorganic hard mask interlayer film such as a SiON film is used, reflection can be suppressed by liquid-wet exposure of a NA of more than 1.0 by an antireflection film of two layers of a SiON film and a BARC. Another advantage of forming a BARC is to have a reduced SiON positive The effect of the trailing photoresist pattern on the top.

The photoresist film of the three-layer photoresist film may be either positive or negative, and may be the same as the commonly used photoresist composition. When the photoresist upper layer film is formed by the above-described photoresist composition, it is preferable to use a spin coating method as in the case of forming the photoresist underlayer film. After the photoresist composition is applied, prebaking is carried out, preferably in the range of 60 to 180 ° C for 10 to 300 seconds. Thereafter, exposure is carried out in accordance with a usual method, and post-exposure baking (hereinafter referred to as "PEB") and development are carried out to obtain a photoresist pattern. Further, the thickness of the photoresist upper film is not particularly limited, and is preferably 30 to 500 nm, particularly 50 to 400 nm.

The method of forming a pattern on the photoresist upper layer film can be carried out by using light lithography having a wavelength of 10 nm or more and 300 nm or less, direct drawing by electron beam, nanoimprinting, or the like, or a combination thereof to form a pattern.

Moreover, an example of the developing method of such a pattern forming method is, for example, alkali development or development using an organic solvent.

Next, etching is performed using the obtained photoresist pattern as a mask. The three-layer process photoresist interlayer film, particularly the inorganic hard mask, is etched using a chlorofluorocarbon-based gas and a photoresist pattern as a mask. Next, the photoresist intermediate layer film pattern, in particular, the inorganic hard mask pattern is used as a mask, and etching of the photoresist underlayer film is performed using oxygen or hydrogen.

The etching of the object to be processed may be carried out by a usual method. For example, if the substrate is SiO ₂ , SiN or a lanthanum low dielectric constant insulating film, etching using a chlorofluorocarbon-based gas as a main component is performed. In the case of -Si, Al, or W, etching mainly composed of a chlorine-based or bromine-based gas is performed. When the substrate is processed by a chlorofluorocarbon-based gas, the three-layer-containing ruthenium-containing intermediate layer is simultaneously peeled off during substrate processing. When the substrate is etched with a chlorine-based or bromine-based gas, the separation of the ruthenium-containing intermediate layer must be carried out by dry etching using a chlorofluorocarbon-based gas after the substrate is processed.

The photoresist underlayer film formed using the photoresist underlayer film material of the present invention is characterized in that it is excellent in etching resistance of the object to be processed.

Further, the workpiece to be processed may be any one of a metal film, a metal carbide film, a metal oxide film, a metal nitride film, and a metal oxide nitride film (hereinafter referred to as a "processed layer") on the semiconductor device substrate. As the film former, for example, any of tantalum, titanium, tungsten, lanthanum, zirconium, chromium, lanthanum, copper, aluminum, and iron, or an alloy thereof may be used.

The substrate is not particularly limited, and those having different materials from the layer to be processed such as Si, α-Si, p-Si, SiO ₂ , SiN, SiON, W, TiN, and Al can be used.

As the layer to be processed, various Low-k films such as Si, SiO ₂ , SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, and Al-Si, and a stop film thereof are usually used. A thickness of 50 to 10,000 nm, especially 100 to 5,000 nm is formed.

An example (three-layer process) of the pattern forming method of the present invention will be specifically described below with reference to Fig. 1 .

In the case of the three-layer process, as shown in FIG. 1(A), after the photoresist underlayer film 3 is formed on the processed layer 2 laminated on the substrate 1 by the present invention, the photoresist intermediate layer film 4 is formed and The photoresist upper film 5 is formed further above.

Next, as shown in FIG. 1(B), the portion 6 of the photoresist upper layer film is exposed, PEB and development are performed to form a photoresist pattern 5a (FIG. 1(C)). Using the thus obtained photoresist pattern 5a as a mask, the photoresist intermediate layer film 4 is etched using a CF-based gas to form a photoresist intermediate layer film pattern 4a (Fig. 1(D)). After the photoresist pattern 5a is removed, the photoresist underlayer film pattern 4a is used as a mask to oxidize the photoresist underlayer film 3 to form a photoresist underlayer film pattern 3a (FIG. 1(E)). Further, after the photoresist intermediate layer film pattern 4a is removed, the processed layer 2 is etched by using the photoresist underlayer film pattern 3a as a mask, and the pattern 2a is formed on the substrate (FIG. 1(F)).

Further, when an inorganic hard mask intermediate film is used, the photoresist intermediate film 4 is inorganic The hard mask intermediate layer film 4a is an inorganic hard mask intermediate layer film pattern 4a.

Further, when the BARC is applied, a BARC layer is provided between the photoresist interlayer film (or the inorganic hard mask interlayer film) 4 and the photoresist upper film 5. BARC etching can be performed by first performing BARC etching and then continuously etching the photoresist interlayer film (or inorganic hard mask interlayer film) 4, or performing only BARC etching and changing the etching device, etc., and then performing the photoresist intermediate. Etching of the film (inorganic hard mask interlayer film) 4.

[Examples]

Hereinafter, the present invention will be specifically described by showing synthesis examples, comparative synthesis examples, examples, and comparative examples, but the present invention is not limited to the description.

[Synthesis of Resin (A)-1~(A)-6]

The resin (A)-1 to (A)-6 was synthesized by the following method.

Further, the method for measuring the molecular weight and the degree of dispersion of the polymer is specifically carried out by the following method.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) in terms of polystyrene were determined by gel permeation chromatography (GPC), and the degree of dispersion (Mw/Mn) was determined.

(Synthesis Example 1) Resin (A)-1

a mixture of 16.8 g of 1,3-adamantanediol, 5.0 g of m-cresol, 15.0 g of 1,7-dihydroxynaphthalene, 100 g of 2-methoxyethanol, and 2.4 g of methanesulfonic acid in a nitrogen gas atmosphere, 110 Stir at °C for 16 hours. After cooling to 70 ° C, 1.1 g of paraformaldehyde was added and stirred for 5 hours. After cooling to room temperature, 200 g of ethyl acetate and 100 g of pure water were added. After the insoluble fraction was filtered, the aqueous layer was removed, and then the organic layer was washed 4 times with 100 g of pure water. The organic layer was dried under reduced pressure to give 33.6 g of Compound (A)-1 as shown below.

The molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC.

Mw: 4,890

Mw/Mn: 3.23

(Synthesis Example 2) Resin (A)-2

A mixture of 8.4 g of 1,3-adamantanediol, 20.0 g of 1,5-dihydroxynaphthalene, 100 g of 2-methoxyethanol, and 2.4 g of methanesulfonic acid was heated and stirred at 110 ° C for 16 hours under a nitrogen atmosphere. After cooling to 70 ° C, 2.0 g of trioxane was added and stirred for 5 hours. After cooling to room temperature, 200 g of ethyl acetate and 100 g of pure water were added. After the insoluble fraction was filtered, the aqueous layer was removed, and then the organic layer was washed 4 times with 100 g of pure water. The organic layer was dried under reduced pressure to give 26.5 g of the resin (A)-2 as shown below.

The molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC.

Mw: 2,930

Mw/Mn: 2.50

(Synthesis Example 3) Resin (A)-3

3.4 g of 1,3-adamantanediol, 2.3 g of 1,3,5-adamantane triol, 20.0 g of 1,5-dihydroxynaphthalene, 80 g of 1-methoxy-2-propanol, 2.4 g of methanesulfonic acid The mixture was heated and stirred at 100 ° C for 16 hours under a nitrogen atmosphere. After cooling to 70 ° C, 1.6 g of paraformaldehyde was added and stirred for 4 hours. After cooling to room temperature, 200 g of ethyl acetate and 100 g of pure water were added. After the insoluble fraction was filtered, the aqueous layer was removed, and then the organic layer was washed 4 times with 100 g of pure water. The organic layer was dried under reduced pressure to give 27.1 g of the resin (A)-3 as shown below.

The molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC.

Mw: 4,660

Mw/Mn: 3.04

(Comparative Synthesis Example 1) Resin (A)-4

To a mixture of 5.0 g of m-cresol, 15.0 g of 1,7-dihydroxynaphthalene, and 2.4 g of trioxane, 2.4 g of methanesulfonic acid was added at 70 ° C under a nitrogen atmosphere, and the mixture was stirred for 5 hours. After cooling to room temperature, 200 g of ethyl acetate and 100 g of pure water were added. After the insoluble fraction was filtered, the aqueous layer was removed, and then the organic layer was washed 4 times with 100 g of pure water. The organic layer was dried under reduced pressure to give 18.0 g of Compound (A)-4 as shown below.

The molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC.

Mw: 1,510

Mw/Mn: 2.02

(Comparative Synthesis Example 2) Resin (A)-5

A mixture of 6.6 g of dicyclopentadiene, 20.0 g of 1,5-dihydroxynaphthalene, 100 g of 2-methoxyethanol, and 2.4 g of methanesulfonic acid was heated and stirred at 110 ° C for 72 hours under a nitrogen atmosphere. After cooling to 70 ° C, 2.0 g of trioxane was added and stirred for 5 hours. After cooling to room temperature, 200 g of ethyl acetate and 100 g of pure water were added. After the insoluble fraction was filtered, the aqueous layer was removed, and then the organic layer was washed 4 times with 100 g of pure water. The organic layer was dried under reduced pressure to give 26.5 g of Compound (A)-5 as shown below.

The molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC.

Mw: 4,350

Mw/Mn: 3.02

(Comparative Synthesis Example 3) Resin (A)-6

A mixture of 16.8 g of 1,3-adamantanediol, 5.0 g of m-cresol, 15.0 g of 1,7-dihydroxynaphthalene, 100 g of 2-methoxyethanol, and 2.4 g of methanesulfonic acid under a nitrogen atmosphere at 110 ° C Stir under heating for 24 hours. After cooling to room temperature, 200 g of methyl isobutyl ketone and 100 g of pure water were added. After the insoluble fraction was filtered, the aqueous layer was removed, and then the organic layer was washed 4 times with 100 g of pure water. The organic layer was dried under reduced pressure to give 30.3 g of Compound (A)-6 as shown below.

The molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC.

Mw: 1,470

Mw/Mn: 2.30

[Examples, Comparative Examples]

(Modulation of photoresist underlayer film material)

20 parts by mass of the above-mentioned resins (A)-1 to 6 and 1 part by mass of the acid generator represented by the following AG1, and dissolved in the FC-430 (manufactured by Sumitomo 3M Co., Ltd.) in 4 parts by mass of the crosslinking agent represented by the following CR1. 100 parts by mass of 0.1% by mass of propylene glycol methyl ether acetate was filtered through a 0.1 μm fluororesin filter to prepare a resist underlayer film forming solution (SOL-1 to 6).

This solution was applied (spin-coated) to a ruthenium substrate, and baked at 250 ° C for 60 seconds to form coating films UDL-1 to 6 having a film thickness of 200 nm. For these films, a wavelength of 193 nm is obtained by a spectral elliptical polarimeter (VASE) with a variable angle of incidence of J.A. Woollam. Learning characteristics (n, k). The results are shown in Table 1. Further, a nanoindentation test was carried out using a Nano-Indenter SA2 type apparatus manufactured by Dongyang Co., Ltd., and the hardness of the coating film was measured. The results are also shown in Table 1.

As shown in Table 1, in the examples (UDL1 to 3), the n value (refractive index) of the photoresist underlayer film satisfies 1.5, and the k value (extinction coefficient) satisfies the target value of the optical characteristic of 0.30 to 0.35, in the 3-layer light. In terms of the underlying film that is resistant, the film thickness of 200 nm or more exhibits a sufficient antireflection effect. Further, in UDL-4 and 6 of the comparative example, the n value and the k value were not within the target value, and the antireflection effect was insufficient.

Further, regarding the hardness, the UDL-1 to 3 of the examples were larger than the UDL-5 of the comparative example, and showed a denser film to form a denser film.

[Examples 1 to 3, Comparative Examples 1 to 3]

(pattern etching test)

The photoresist underlayer film material (UDL-1~6) was coated (spin-coated) onto a 300 mm Si wafer substrate having a SiO ₂ film having a thickness of 200 nm, and baked at 250 ° C for 60 seconds to form a film thickness of 200 nm. The lower layer film of the photoresist (Examples 1-3, Comparative Examples 1-3). The ruthenium-containing photoresist intermediate layer polymer SOG-1 prepared according to the usual method is coated thereon, baked at 220 ° C for 60 seconds to form a photoresist film having a film thickness of 35 nm, and coated with a photoresist upper layer film material (ArF The SL photoresist solution was baked at 105 ° C for 60 seconds to form a photoresist upper film having a film thickness of 100 nm. The infiltrated protective film (TC-1) was applied to the photoresist upper layer film, and baked at 90 ° C for 60 seconds to form a protective film having a film thickness of 50 nm. The upper photoresist is prepared by dissolving a resin, an acid generator, and an alkali compound having a composition shown in Table 2 in a solvent containing 0.1% by mass of FC-430 (manufactured by Sumitomo 3M Co., Ltd.). The filter is filtered to prepare.

(ArF single-layer photoresist polymer 1) (u=0.40, v=0.30, w=0.30 Mw7,800)

PGMEA 2-methoxyacetate

(ArF containing ruthenium intermediate layer polymer) (o=0.20, p=0.50, q=0.30 Mw=3,400)

The wetting protective film material (TC-1) was prepared by dissolving a resin having a composition shown in Table 3 in a solvent and filtering it with a filter made of a fluororesin of 0.1 μm .

Protective film polymer: the following structural formula

Next, the ArF immersion exposure apparatus (Nikon (manufactured by Nikon); NSR-S610C, NA1.30, σ 0.98/0.65, 35-degree dipole illumination s polarized illumination, 6% half-tone phase shift mask) was changed. The exposure amount was exposed to one side, baked at 100 ° C for 60 seconds (PEB), developed with 2.38 mass % tetramethylammonium hydroxide (TMAH) aqueous solution for 30 seconds, and a positive type of photoresist line width from 50 nm to 30 nm was obtained at a pitch of 100 nm. Line and space pattern.

Next, using the Tokyo Electric Power Co., Ltd. to create the etching apparatus Telius, the photoresist pattern was used as a mask for the processing of the ruthenium-containing intermediate layer, and the ruthenium-containing intermediate layer was used as the mask underlayer film. Processing of the SiO ₂ film of the cover. The results are shown in Table 4.

. The etching conditions are as follows.

Transfer conditions to the SOG film of the photoresist pattern.

. Transfer conditions to the underlying film of the SOG film.

. Transfer conditions to the SiO ₂ film.

The pattern profile was observed by an electron microscope (S-4700) manufactured by Hitachi, Ltd., and the shapes were compared and organized as shown in Table 4.

【Table 4】

As shown in Table 4, since the photoresist shape after development of Comparative Example 1 was poor, etching evaluation could not be performed. The reason is considered to be due to the n value of UDL-4. The combination of k values is far from the optimum value, so the anti-reflection effect is not good.

Further, in Comparative Example 2, although the shape of the photoresist after development and the like were good, the pattern width after the transfer of the substrate was changed as the line width of the photoresist line formed by the exposure was changed, and a pattern was formed at a line width of about 40 nm. distortion.

Further, in Comparative Example 3, the shape was not distorted until the pattern size was 40 nm or less, but the etching shape after the substrate transfer was not good.

On the other hand, Examples 1 to 3, as shown in Table 1 above, have n values that can be practically applied to the underlayer film of the 3-layer photoresist for immersion lithography. The k value, as shown in the pattern evaluation shown in Table 4, was good in the shape of the photoresist after development, after the oxygen etching, and after the substrate processing and etching.

Further, in Examples 1 to 3, it was found that there was no distortion until the pattern size was 35 nm or less, and the twist resistance was high. Therefore, as in the case of the layer film of the present invention, by using one The underlayer film can form a dense film having a hardness higher than 0.60 GPa, and high twist resistance can be obtained.

As described above, the photoresist underlayer film material of the present invention has an ideal optical property to provide a sufficient antireflection effect, and is excellent in distortion resistance during etching, and can be effectively applied to a multilayer photoresist which is processed as an ultrafine and high precision pattern. Process, especially for the 3-layer photoresist process.

Further, the present invention is not limited to the above embodiment. The above-described embodiments are exemplified, and have substantially the same configuration as the technical idea described in the patent application scope of the present invention, and the same effects are all included in the technical scope of the present invention.

1‧‧‧Substrate

2‧‧‧Processed layer

2a‧‧‧ pattern

3‧‧‧Photoresist underlayer film

3a‧‧‧Photoresist underlayer film pattern

4‧‧‧Photoresist interlayer film (inorganic hard mask interlayer film)

4a‧‧‧Photoresist interlayer film pattern (inorganic hard mask intermediate film pattern)

5‧‧‧Photoresist upper film

5a‧‧‧resist pattern

6‧‧‧Parts used

1(A) to (F) are explanatory views showing a (three-layer photoresist processing process) of the pattern forming method of the present invention.

Figure 2 shows that the fixed underlayer film has a refractive index n of 1.5, a k value of 0.6, and a film thickness of 500 nm in a 3-layer process, such that the n value of the intermediate layer is 1.5, the k value is 0 to 0.4, and the film thickness is 0 to 400 nm. A graph of the relationship of substrate reflectance when the range is changed.

3 shows that the refractive index n of the fixed underlayer film in the 3-layer process is 1.5, the k value is 0.2, the n value of the intermediate layer is 1.5, and the k value is 0.1, and the substrate reflectance is changed when the film thickness of the lower layer and the intermediate layer is changed. A graph of the relationship.

4 shows that the refractive index n of the fixed underlayer film in the 3-layer process is 1.5, the k value is 0.6, the n value of the intermediate layer is 1.5, and the k value is 0.1, and the reflectance of the substrate when the film thickness of the lower layer and the intermediate layer is changed is shown. A graph of the relationship.

Claims (11)

A photoresist underlayer film material comprising: at least one or more compounds represented by the following general formulae (1-1) and/or (1-2), and one or more of the following formulas (2) a compound obtained by condensing one or more compounds represented by the following formula (3) and/or an equivalent thereof; (In the general formulae (1-1) and (1-2), R ¹ to R ⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an isocyanate group, a glycidoxy group, a carboxyl group, an amine group, or a carbon number. Any one of an alkoxy group of 1 to 30, an alkoxycarbonyl group having 1 to 30 carbon atoms, an alkoxycarbonyl group having 1 to 30 carbon atoms, or a saturated or unsaturated organic group having 1 to 30 carbon atoms which may be substituted Further, two substituents arbitrarily selected from R ¹ to R ⁴ or R ⁵ to R ^{8 may} be bonded to each other to form a cyclic substituent; however, the general formula (1-1) is not included. And (1-2) is a substituted or unsubstituted condensed aromatic ring having three or more aromatic rings); (In the formula (2), X is an integer of 2 to 4.); Y-CHO (3) (in the formula (3), Y is a hydrogen atom or a carbon number of 1 to 30 which may be substituted Price organic base.). The photoresist underlayer film material according to the first aspect of the invention, wherein the photoresist underlayer film material further contains one or more of a crosslinking agent, an acid generator, and an organic solvent. A pattern forming method for forming a pattern on a workpiece, characterized in that it comprises at least the step of forming a photoresist on the object to be processed using a photoresist underlayer film material as claimed in claim 1 or 2 a lower film, and a photoresist intermediate layer film is formed on the underlying film, using a germanium-containing photoresist interlayer film material, and a photoresist of the photoresist composition is used on the photoresist interlayer film. Forming a photoresist upper layer film on the upper resist film, forming a circuit pattern on the photoresist upper layer film, etching the photoresist intermediate layer film by using the patterned photoresist upper layer film as a mask, and forming the patterned light The resist interlayer film is etched as a mask, and the processed object is etched by using the patterned photoresist underlayer film as a mask to form a pattern on the object. A pattern forming method for forming a pattern on a workpiece, characterized in that it comprises at least the step of forming a photoresist on the object to be processed using a photoresist underlayer film material as claimed in claim 1 or 2 a lower film, and a photoresist intermediate layer film formed on the underlying film, using a germanium-containing photoresist interlayer film material, and an organic anti-reflective film (BARC) formed on the photoresist interlayer film, And forming a photoresist upper layer film on the BARC by using the photoresist upper layer film material of the photoresist composition to form a 4-layer photoresist film, forming a circuit pattern on the photoresist upper layer film, and forming the patterned photoresist The BAR film and the photoresist interlayer film are etched as a mask, and the photoresist underlayer film is etched by using the patterned photoresist intermediate film as a mask, and further, the patterned light is formed The underlayer film is etched as a mask to form a pattern, and a pattern is formed on the object to be processed. A pattern forming method, which is a method of forming a pattern on a workpiece, The method comprises the steps of: forming a photoresist underlayer film on the object to be processed by using the photoresist underlayer film material according to claim 1 or 2, and forming a selective auto-oxidation on the underlayer film. An inorganic hard mask interlayer film of any one of a film, a tantalum nitride film, a tantalum oxide film, and an amorphous germanium film, and a light of a photoresist composition is used on the inorganic hard mask interlayer film Forming a photoresist upper layer film on the upper resist film, forming a circuit pattern on the photoresist upper layer film, and etching the inorganic hard mask intermediate layer film by using the patterned photoresist upper layer film as a mask, and forming the inorganic hard mask intermediate layer film The inorganic hard mask intermediate layer film of the pattern is used as a mask to etch the photoresist underlayer film, and further, the formed photoresist is etched by using the patterned photoresist underlayer film as a mask, and on the processed body Form a pattern. A pattern forming method for forming a pattern on a workpiece, characterized in that it comprises at least the step of forming a photoresist on the object to be processed using a photoresist underlayer film material as claimed in claim 1 or 2 An underlayer film is formed on the underlayer film of the photoresist, and a film selected from the group consisting of a tantalum oxide film, a tantalum nitride film, a tantalum oxide film, and an amorphous germanium film is formed on the underlayer film. An inorganic hard mask interlayer film, an organic anti-reflection film (BARC) is formed on the inorganic hard mask interlayer film, and a photoresist upper layer film is formed on the BARC by using a photoresist composition upper photoresist film material, And forming a 4-layer photoresist film, forming a circuit pattern on the photoresist upper layer film, and etching the BARC and the photoresist intermediate layer film by using the patterned photoresist upper layer film as a mask, and forming the photoresist layer The patterned photoresist intermediate layer film is used as a mask to etch the photoresist underlayer film, and further, the patterned photoresist underlayer film is used as a mask to etch the object to be processed, and a pattern is formed on the object to be processed. . The pattern forming method of claim 5, wherein the inorganic hard mask interlayer film is formed by a CVD method or an ALD method. The pattern forming method according to any one of claims 3 to 6, wherein the patterning method of the photoresist upper layer film is performed by using a wavelength of 10 nm or more and 300 nm or less. Any of the light lithography, direct drawing by electron beam, and nanoimprint, or a combination thereof, to form a pattern. The pattern forming method according to any one of claims 3 to 6, wherein the developing method in the pattern forming method is alkali development or development using an organic solvent. The pattern forming method according to any one of claims 3 to 6, wherein the processed system has a metal film, a metal carbide film, a metal oxide film, a metal nitride film, and a metal oxide nitrogen on the semiconductor substrate. Any one of the film-forming films. The pattern forming method of claim 10, wherein the metal is any one of tantalum, titanium, tungsten, lanthanum, zirconium, chromium, lanthanum, copper, aluminum, and iron, or an alloy thereof.